1. Field of the Invention
The present invention relates to a thin film magnetic head that has a plurality of electrode terminals formed on the same surface as a head element formation surface of a slider substrate, on which a magnet head element is laminated.
In particular, the present invention relates to a thin film magnetic head that has electrode terminals and an electronic component that can prevent a probe pin from sliding off of and being disengaged from the electrode terminals at the time of probing, and that can prevent a short circuit between adjacent electrode terminals caused by a bonding metal that has flowed outside the electrode terminals at the time of bonding, even if an area of an electrode terminal becomes small or even if a gap between adjacent electrode terminals narrows due to an increased number of electrode terminals to be provided.
2. Description of Conventional Technology
For the production of thin film magnetic heads, various laminate patterns are sequentially formed on a wafer substrate after multiple integration processes.
As a result, normally tens of thousands of elements for a thin film magnetic head structure are formed in a matrix on a single wafer substrate.
In the process for producing such thin film magnetic heads, the wafer substrate is cut into a plurality of bar-shaped blocks during the production process after the integration process. Thereafter, the bar-shaped wafer substrate is cut into individual sliders (i.e., the smallest unit of thin film magnetic heads), which thereafter go through final processing.
As shown in FIG. 10, for example, each slider (i.e., thin film head) includes a slider substrate 330 that has an ABS (air bearing surface) 330a processed so as to obtain an appropriate flying height, a magnetic head element 300 provided on an element formation surface 330b that is a side surface perpendicular to the ABS 330a, a protector 332 provided on the element formation surface 330b to cover the magnetic head element 300, six electrode terminals 333, 334, 335, 336, 337 and 338, for example, that are exposed from a surface of the protector 332 (there is also a case of four electrode terminals).
The magnetic head element 300 includes, as main components, a magnetoresistive effect (MR) reading head element 301 for reading out data signals from a magnetic disk, and an inductive writing head element 302 for writing data signals onto the magnetic disk.
Of the plurality of electrode terminals, the electrode terminals 333 and 334, for example, are respectively electrically connected to the MR reading head element 301, and the electrode terminals 335 and 336, for example, are respectively electrically connected to the inductive writing head element 302. The electrode terminals 337 and 338, for example, are connected to a heater embedded in the slider for fine-tuning the flying height of the thin film magnetic head. As discussed above, the electrode terminals 337 and 338 may not exist.
For assuring the quality of the thin film magnetic heads, various measurements, such as inductance characteristic of the reading head element 301, a coil resistivity value, MR characteristic of the writing head element 302, a heater resistivity value and an insulation resistivity, become necessary with the above-discussed electrode terminals. At that time, tests for measuring desired characteristic of each element and the like are performed by attaching a measurement pin (probe pin) for the measurement onto the electrode terminal.
The conventional art shown in FIG. 10 includes six electrode terminals. Because there is a relatively sufficient space on the element formation surface 330b on which the electrode terminals are provided, an area for each electrode terminal can be made large, and the gap between adjacent electrode terminals can be increased.
As a result, the measurement pin rarely slides off, and is rarely disengaged from, the electrode terminals at the time of probing. Further, there is a small possibility that the bonding metal flows outside an electrode terminal and causes a short circuit between adjacent electrode terminals at the time of bonding the electrode terminals.
However, presently the head sizes are becoming smaller to make the head more compact. Moreover, with a new structure of a final product, the number of electrode terminals is tending to increase to provide multiple functions in the head. For example, the possibility that around ten electrode terminals are to be provided is now extremely high. Product development has actually proceeded based on such a direction.
According to such a tendency, the size of each electrode terminal (i.e., pad) must be reduced. However, with a reduced size of the electrode terminals, measurement errors due to disengagement of the measurement pin from the pad at the time of probing tends to increase. In addition, because the gap between adjacent electrode terminals is narrowed, the chance of a short circuit between adjacent electrode terminals at the time of bonding the electrode terminals tends to increase.
The present invention was conceived based on such facts. An object of the present invention is to provide a thin film magnetic head with electrode terminals that can reduce measurement errors by preventing the measurement pin (probe pin) from sliding off and disengaging from the electrode terminals at the time of probing, and that can prevent a bonding metal from flowing outside the electrode terminal at the time of bonding to prevent the occurrence of a short circuit between adjacent electrode terminals, even if the area of the electrode terminals is reduced or even if the gap between the adjacent electrode terminals is reduced due to the increase in the number of electrode terminals to be provided and the like.